• ETRI Journal
• /
• v.30 no.5
• /
• pp.674-684
• /
• 2008

This paper proposes a dual addressing scheme (DAS) for IPv6 over IEEE 802.15.4 wireless sensor networks (WSN). DAS combines a global unicast address to cope with association link changes and node mobility, and it links local addresses to lighten the overhead of the system to save energy and resources. This paper describes DAS address formats, address autoconfiguration, and address translation tables in the gateway. A detailed description of DAS is provided through examples. Simulations are performed to demonstrate the performance improvements of the DAS compared with the IPv6-based WSN, which uses the conventional single address.

• Journal of Korean Institute of Industrial Engineers
• /
• v.25 no.3
• /
• pp.404-410
• /
• 1999

A scheme of more exact overflow probability analysis is proposed for traffic regulated by dual leaky bucket. To each regulated traffic stream is allocated bandwidth and buffer independent of other traffic stream and overflow occurs when total bandwidth or buffer allocated to each traffic exceed link capacity or physical buffer size. Ratio of buffer and bandwidth allocated to each traffic stream is assumed to be constant, and this ratio is larger than the ratio of physical buffer and bandwidth due to buffer sharing effect. Numerical experiments show that this sharing effect have significant influence on overflow probability and effective bandwidth.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.2
• /
• pp.227-235
• /
• 1999

In this paper a vibration control fo a one-link flexible beam is considered. At first a state-space model for a flexible beam is derived by using the assumed-modes approach. Based on this model the transfer function between the applied torque and the tip deflection fo the beam is presented because it is convenient to apply our method. In general there exist some control difference due to flexibility of the beam so we adop a forward-passive controller to reduce these phenomena. And a complex dual-input describing function compensator is used to control the tip deflection. The stabiltiy and the performance of the closed-loop system are analyzed. Finally the validity of the derived model and the effectiveness of proposed controller are confirmed throuth simula-tions and experiments.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.3
• /
• pp.225-235
• /
• 2009

A common procedure of restoration of endodonticlly treated tooth with fiber-reinforced post is followed by core build-up after post cementation. However, this technique is complex and time-consuming. The aim of this study was to compare fracture strength of premolar, restored with various methods of core fabrications on fiber-reinforced posts and casting metal restoration. Forty five freshly extracted human mandibular premolars were obtained and devided into 5 groups acconding to the type of post and methods of core build-up. In Group A, D.T. $Light-post^{(R)}$ were cemented with $DUO-LINK^{TM}$ and then $LIGHT-CORE^{TM}$ was used for core restoration. In Group B, D.T. $Light-post^{(R)}$ and $DUO-LINK^{TM}$ were used for cementing in the postspace, and $DUO-LINK^{TM}$ was used again for core restoration. In Group C, $Light-post^{(R)}$ bonding and the core build-up were performed simultaneously by using $DUO-LINK^{TM}$. In Group D, $LuxaPost^{(R)}$ was bonded by using $LuxaCore^{(R)}-Dual$. Again, $LuxaCore^{(R)}-Dual$ was used for core restoration. In Group E, $LuxaPost^{(R)}$ bonding and the core build-up were performed simultaneously by using $LuxaCore^{(R)}-Dual$. Axial reduction was formed parallelly as possible and 45 degree bevel was made at buccal occlusal surface. Crowns were fabricated and cemented. Each tooth was embedded in self-curing acrylic resin to the level of 2mm below the CEJ. Specimens were fixed on universal testing machin such that the axis of the tooth was at 45 degree inclination to the horizontal plane, and compressive force was applied at a crosshead speed of 1mm/min until failure occurred. The mean fracture strength was the highest in group A followed by descending order in group B, D, E and C. However, there were no statistically significant differences between groups with regard to the fracture strength. The type of the post or build-up methods of the core does not seem to influence the fracture strength.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.7A
• /
• pp.528-534
• /
• 2012

In order to achieve high capacity and reliable link quality of the overlay convergent networks with the cognitive networking based on the advanced capability of the mobile terminal, a Distributed Wireless Communication System (DWCS) can provide the capability of enhancing the link quality. This paper has considered virtual cell: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on radio resource monitering. The considered system constructs DVC for multi-user high-rate data transmission, and the DWCS system exploits space-time trellis codes i.e., STTC to improve a spectral efficiency. The effects of imperfect CSI(channel state information) on the system performance has also been investigated.

• Proceedings of the KIPE Conference
• /
• 2019.07a
• /
• pp.207-209
• /
• 2019

This paper proposes a grid-tied photovoltaic (PV) system, consisting of Voltage-fed dual-active-bridge (DAB) dc-dc converter with single phase inverter. The proposed converter allows a small dc-link capacitor, so that system reliability can be improved by replacing electrolytic capacitors with film capacitors. The double line frequency free maximum power point tracking (MPPT) is also realized in the proposed converter by using Ripple Correlation method. First of all, to eliminate the double line frequency ripple which influence the reduction of DC source capacitance, control is developed. Then, a designing of Current control in DQ frame is analyzed and to fulfill the international harmonics standards such as IEEE 519 and P1547, $3^{rd}$ harmonic in the grid is directly compensated by the feedforward terms generated by the PR controller with the grid current in stationary frame to achieve desire Total Harmonic Distortion (THD). 5-kW PV converter and inverter module with a small dc-link film capacitor was built in the laboratory with the proposed control and MPPT algorithm. Experimental results are given to validate the converter performance.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.2
• /
• pp.177-187
• /
• 2000

In the past several years, many systems which adopted ring topology with high-speed unidirectional point-to-point links have emerged to overcome the limit of bus for interconnection network of clustered multiprocessor system. However, rapid increase of processor speed and performance improvement of local bus and memory system limit scalability of system with point-to-point link of standard bandwidth. Therefore, necessity to extend bandwidth is emphasized. In this paper, we adopt PANDA system as base model, which is clustering-based multiprocessor system. By simulating a model adopting commercial processor and local bus specification, we show that point-to-point link is bottleneck of system performance, and bandwidth expansion by more than 200% is needed. To expand bandwidth of interconnection network, it needs excessive design cost and time to develop new point-to-point link with doubled bandwidth. As an alternative to double bandwidth, we propose several ways to implement dual ring -simple dual ring, transaction-separated dual ring, direction-separated dual ring- by using off-the-shelf point-to-point links with IEEE standard bandwidth. We analyze pros. and cons. of each model compared with doubled-bandwidth single ring by simulation.

• Journal of Korean Dental Science
• /
• v.8 no.2
• /
• pp.49-56
• /
• 2015

Purpose: The effect of accelerated aging on color stability of various dual-cured self-adhesive resin cements were evaluated in this study. Materials and Methods: Color stability was examined using three different brands of dual-cured self-adhesive resin cements: G-CEM LinkAce (GC America), MaxCem Elite (Kerr), and PermaCem 2.0 (DMG) with the equivalent color shade. Each resin cement was filled with Teflon mold which has 6 mm diameter and 2 mm thickness. Each specimen was light cured for 20 seconds using light emitting diode (LED) light curing unit. In order to evaluate the effect of accelerated aging on color stability, color parameters (Commission Internationale de l'Eclairage, CIE $L^*$, $a^*$, $b^*$) and color differences (${\Delta}E^*$) were measured at three times: immediately, after 24 hours, and after thermocycling. The $L^*$, $a^*$, $b^*$ values were analyzed using Friedman test and ${\Delta}E^*$ values on the effect of 24 hours and accelerated aging were analyzed using t-test. These values were compared with the limit value of color difference (${\Delta}E^*=3.7$) for dental restoration. One-way ANOVA and Scheff's test (P<0.05) were performed to analyze each ${\Delta}E^*$ values between cements at each test period. Result: There was statistically significant difference in comparison of color specification ($L^*$, $a^*$, $b^*$) values after accelerated aging except $L^*$ value of G-CEM LinkAce (P<0.05). After 24 hours, color difference (${\Delta}E^*$) values were ranged from 2.47 to 3.48 and $L^*$ values decreased and $b^*$ values increased in all types of cement and MaxCem Elite had high color stability (P<0.05). After thermocycling, color change's tendency of cement was varied and color difference (${\Delta}E^*$) values were ranged from 0.82 to 2.87 and G-CEM LinkAce had high color stability (P<0.05). Conclusion: Color stability of dual-cured self-adhesive resin cements after accelerated aging was evaluated and statistically significant color changes occurred within clinically acceptable range.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.3
• /
• pp.27-34
• /
• 2005

This paper presents a three phase Line-Interactive uninterruptible power supply(UPS) system with dual converter structure. The three phase UPS system consists of two active power compensator topologies. One is a series active compensator, which works as a voltage source in phase with the source voltage to have the sinusoidal source current and high power factor under the deviation and distortion of the source voltage. The other is a parallel active compensator, which works as a conventional sinusoidal voltage source in phase with the source voltage, providing to the load a regulated and sinusoidal voltage with low total harmonic distortion(THD). This paper presents in the series and parallel active compensator charging method depending on the amplitude of the source voltage. The conventional Line-Interactive UPS system is responsible for the DC charging and output voltage regulation at the same time, but UPS system with dual converter structure, a series active compensator can also charge the DC link. Therefore the charging algorithm using the series and parallel compensator needs to be researched. Therefore, by making the DC link voltage stable it can contribute the stability of series and parallel compensator. The simulation and experimental result are depicted in this paper to show the effect of the proposed algorithm.

• Korean Journal of Social Welfare
• /
• v.60 no.3
• /
• pp.253-274
• /
• 2008

The link between work life and family life is an essential subject matter in understanding the lives of dual-earner couples. Concepts of spillover and crossover explain the link between work and family. The present study examines both the positive and negative aspects in these processes. The data come from the Sloan Working Families Study conducted by the Alfred P. Sloan Center on Parents, Children, and Work and NORC at the University of Chicago. The Experience Sampling Method employed explores directly the daily life experiences of the participants. The data were analysed using t-test. Both spillover and crossover were found in the lives of dual-earner couples in this study. Men and women brought happy emotions at work to home, but the data provide limited support for spillover of negative emotions. Gender differences were more apparent in examining the process of crossover. Men appear responsive to the positive and negative emotional experiences their spouse brought home while women were found not to be responsive to their spouses' positive emotional experiences at work. Furthermore, the analysis revealed an interesting trend concerning the emotions of working couples in that they generally seem to recover to their average level of emotions once home. This suggests that home can be a respite from strong emotions, a comforting place. By looking closely into the emotions experienced by working parents in their daily lives, this study adds contextual understanding concerning the link between work and family life. The findings on the effects of positive experiences at work invite social work practitioners and researchers to further investigate the phenomena of spillover and crossover processed in greater detail, taking into account this contextual aspect of family life as well as the work life of dual-earner couples.